Electric motor brake

Abstract

The present invention provides an internal braking system for use with electric motors, particularly electric motors used with rotary actuators. The braking system includes a brake which has a spindle disposed at least partially between the rotor and a shaft. An annular engagement portion of the brake is integrally connected to the spindle through a conical portion. The brake is forced against a stationary friction member when the motor is de-energized. The brake is preferably made from a polymeric alloy having self-lubrication properties.

What is claimed is: 
     
       1. A brake system for use in an electric motor which can be energized or de-energized, said motor having a stator and a rotor mounted about a shaft in operative relationship with said stator, said stator and said rotor both being mounted within a framework, said brake system comprising: an integral brake member formed of a polymer having self-lubrication properties, said brake member including a spindle and a brake disk affixed to said spindle and extending radially from said spindle, wherein said spindle is disposed at least partially between said shaft and said rotor;   a friction member attached to said framework proximate said brake disk and configured for selective frictional engagement with said brake disk; and   a resilient member for biasing said brake disk towards said friction member when said motor is de-energized, wherein said brake member comprises an acetal polymer mixed with glass beads.   
     
     
       2. A brake for use with an electric motor having a rotatable rotor and a fixed shaft about which said rotor rotates, said brake comprising: a spindle at least partially disposed between said rotor and said shaft, wherein said rotor is fixed to said spindle and said spindle rotates about said shaft; and   a brake disk integral with said spindle and extending radially outward from said spindle external to said rotor, wherein said brake disk includes an annular braking surface and a support portion extending between said annular braking surface and said spindle, wherein said support portion is conical, the brake further comprising a friction ring affixed to said brake disk, wherein said brake is made of an acetal polymer mixed with glass beads.   
     
     
       3. A brake system for use in an electric motor which can be energized or de-energized, said motor having a stator and a rotor mounted about a shaft in operative relationship with said stator, said stator and said rotor both being mounted within a framework, said brake system comprising: an integral brake member including a spindle and a brake disk affixed to said spindle and extending radially from said spindle, wherein said spindle is disposed at least partially between said shaft and said rotor;   a friction member attached to a portion of said framework proximate said brake disk and configured for selective frictional engagement with said brake disk; and   a resilient member for biasing said brake disk towards said friction member when said motor is de-energized, wherein said portion of said framework is movable between a contact position where said brake disk can move into contact with said portion and a retracted position where said brake disk is prevented from contacting said portion.   
     
     
       4. The brake system of claim 3, wherein said integral brake member is formed of a polymer having self-lubrication properties. 
     
     
       5. The brake system of claim 4, wherein said rotor is fixed to said spindle and said spindle is rotatably mounted on said shaft. 
     
     
       6. The brake system of claim 5, wherein said integral brake member further includes a friction ring attached to said brake disk.